A fiber-reinforced composite material formed from reinforcing fibers and a matrix resin is lightweight and has excellent mechanical characteristics. Therefore, fiber-reinforced composite materials are widely used in structural materials for aircrafts, wind turbine blades, vehicles, ships, buildings and the like; and sports instruments such as golf shafts, fishing poles, tennis rackets and the like.
Various methods are used in the production of a fiber-reinforced composite material. Among others, a method of forming a prepreg in a sheet form, a tape form or a string form, by impregnating a reinforcing fiber substrate with a matrix resin, and utilizing this as an intermediate substrate, is widely used. For the matrix resin used in a prepreg, a thermosetting resin or a thermoplastic resin is used; however, a thermosetting resin is used more frequently.